 They're blind, which is good, but they have really, really, really, really good hearing, which is bad for everybody. And basically, if you're doing anything, making any more noise than, say, breathing, they're going to hear it and they're on you instantly. They're sort of vaguely buggish and spider-like monsters with lots of teeth. And they do bad things to the people they catch. And they're super fast, too, like they can scale a skyscraper in a couple seconds. They're very creepy monsters.